(1) Field of the Invention
The present invention relates to a plasma television and a power supply control device.
(2) Description of the Related Art
One well known conventional prior art method to protect a television receiver, is to prohibit the main power supply of a microcomputer from being set to ON after the number of protection operations to set the main power supply to OFF reaches a predetermined number (Refer to Japanese Patent Laid-Open No. H4-79583).
Another well known prior art method for protection of a television receiver is to set a switching circuit of a television to OFF when noises are detected for a predetermined time in the main body of the television receiver (Refer to Japan Utility Model Publication No. 3087790).
Still a further well known prior art method for protection of a television receiver is to disable a high voltage output circuit when the number of judgments that examine the duration of an abnormal state detection signal with preset time intervals reaches the predetermined number (Refer to Japanese Patent Laid-Open No. H10-327372).
In above-mentioned prior arts, measures are adapted that prevent a protection target apparatus from shutting off the power supply when noises temporally flow in the apparatus.
In apparatuses, such as television sets, it is required that the main power supplies be shut off when abnormal voltage values are detected due to some circuit malfunction within the apparatus, which prevents abnormal voltages from flowing in a display panel. However, in general, the main power supplies are generally not shut off when the abnormal voltages that are detected are due to temporal inflow of noises. Judgment as to whether the detection of abnormal voltage values is due to a real malfunction or due to simple inflow of noises can be made accurately by repeating the above-mentioned detection process.
Among various circuits that constitute an apparatus, the malfunctions of some circuits may directly cause the failure of the above-mentioned display panel, and the malfunctions of other circuits may indirectly cause the failure of the above-mentioned display panel. Therefore, there are various circuits with different malfunction severities mixed in an apparatus. However, attention is not paid to the different malfunction severities of various portions that constitute an apparatus.
Therefore, there is an inappropriate case where the hasty decision is made to shut off a power supply of an apparatus even though there is enough time to determine if the detection of abnormal voltage values have been due to a real malfunction or due to simple inflow of noises. Further, there is another inappropriate case where the above-mentioned detection process may be repeated many times despite the urgency to shut off the power supply at once, with the adverse effect caused by actual malfunction of a circuit.